1. Field of the Invention
The present invention relates generally to the field of packet-switched network audio conferencing. More specifically, the present invention discloses a method for large-scale, fault-tolerant audio conferencing in a purely packet-switched network.
2. Statement of the Problem
The most common method to route calls for an audio conference is to control a local switch in a GSTN (globally switched telephony network). That is, a physical point-to-point connection is made between each piece of equipment in the network to create an overall point-to-point audio connection for the call. However, such a switch-controlled application can only route calls to devices connected to the switch, limiting the overall size of the system and limiting the geographic distribution of multipoint control units (MCUs) within the system. In addition, call transfer (e.g., from one MCU to another) requires that the connection from the switch to the new endpoint be established and the path to the transferring endpoint be torn down, thus limiting its use in a large-scale audio conferencing system.
Another conventional method to route calls for an audio conference is to interface with the network signaling layer (SS7/C7) directly.
Packet-switched call routing, on the other hand, facilitates dynamic call routing and call transfer during a call. That is, no dedicated point-to-point connection is required in a packet-switched network. Each packet, including the call data and associated-control, is sent individually to a destination address and the physical route taken from one endpoint to another can vary from packet to packet, eliminating the need for a dedicated circuit for each call. Thus, a call can be routed or even transferred within the packet-switched network simply by renegotiating the end point address. A need exists to provide audio conferencing using packet-switched call routing.
There is a need for audio conferencing implemented on a purely packet-switched network that provides both scalability and fault tolerance. Specifically, a need exists to monitor a pool of MCUs to determine which MCU can best handle the conference, and to dynamically route calls within the purely packet-switched network so that a conference participant in one conference call can be transferred to another conference call and further, entire conferences can be transferred to other MCUs in the MCU pool without interrupting the audio conference (i.e., without tearing down connections and reestablishing the connections within the packet-based network). A need also exists for audio conferencing for both receive-only or passive broadcast participants. Specifically, a need exists to provide a voice stream to the endpoints connected to the conference but that do not actively participate in the conference itself (i.e., do not contribute to the conference voice stream). Yet another need exists for full service audio conferencing using both high-touch (operator assisted) or reservation based audio conferencing and-automated or xe2x80x9cad hocxe2x80x9d audio conferencing using the same platform. Specifically, a need exists to provide conferencing on a reservation basis and on an impromptu basis by monitoring a pool of MCUs to efficiently establish conferences in the packet-based network.
None of the prior art references discussed above disclose large-scale, fault-tolerant audio conferencing implemented in a purely packet-switched network.
This invention provides an audio conferencing method implemented on a purely packet-switched network that provides scalability and fault tolerance.
A primary object of the present invention is to provide large-scale, fault tolerant audio conferencing using dynamically routed, call transfer in a purely packet-switched network. That is, the present invention monitors a pool of MCUs so that conferences can be efficiently established and routed to different MCUs when an MCU approaches capacity or when an MCU has to be taken out of service. As the audio conferencing method is implemented in a purely packet-switched network, the destination of each audio packet can be rerouted seamlessly without interrupting the audio conference.
Another object of the present invention is to provide an audio conferencing method for receive-only or passive participants. That is, participants that do not actively contribute to the conference can be accommodated (i.e., receive the conference output or voice stream).
Yet another object of the present invention is to provide full service audio conferencing using both high-touch or reservation-based audio conferencing and automated or xe2x80x9cad hocxe2x80x9d audio conferencing on the same platform. That is, a conference need not be reserved against a dedicated MCU and instead, the method of the present invention allows a pool of MCUs to be monitored, thus allowing for both advance conference reservations and ad-hoc conferences.
The present invention discloses a method of large-scale fault-tolerant audio conferencing in an audio conferencing system using a purely packet-switched network. According to the method of the present invention, an endpoint places a call to a conference gatekeeper indicating an audio conference (i.e., containing a location-request or LRQ signal). The conference gatekeeper determines whether the call contains sufficient information to establish the audio conference. If there is insufficient information, the endpoint is connected to an interactive voice response (IVR) server that obtains sufficient information (i.e., an account number) from the endpoint. Either way, a conference allocation and control system (CACS) linked to the conference gatekeeper selects an available multipoint control unit (MCU) to either host the audio conference if the audio conference has not been established yet, or the MCU that is already hosting the audio conference. The CACS then responds to the endpoint with routing instructions (i.e., a location-found or LCF signal) indicating the selected MCU. The endpoint then uses the routing instructions to connect to the selected MCU, or where the endpoint was initially connected to the IVR server to gather additional information, the endpoint is transferred from the IVR server to the selected MCU. Once connected, the MCU mixes input from all of the endpoints in the audio conference and forms a voice stream, which the MCU then returns to each endpoint in the audio conference.
Once an audio conference is established according to the method of the present invention, the audio conference participants (i.e., endpoints connected to the MCU in the audio conference) can dial-out from the MCU to bring additional participants (i.e., another endpoint) into the audio conference. In addition, the established audio conference supports full service audio conferencing (i.e., both reservation-based, and ad hoc). Furthermore, the established audio conference supports dynamic routing which permits an operator to service multiple MCUs, for the MCUs to be geographically dispersed, and for an audio conference participant and/or an entire audio conference to be moved between MCUs. The audio conference can also be broadcast from a streaming protocol server to passive participants. As such, the audio conference established according to the method of the present invention using a purely packet-switched network can be both large scale, and is fault-tolerant.